208 TRILLIUM. 



tudinally. Owing to the difficulty of obtaining good 

 sections, and the interference of the starch, the further 

 study of the bundles is deferred till they are reached in 

 the aerial stem. 



Cut a thin slice from the surface of the rootstock, and 

 under low power, notice 



5. The shape of the epidermal cells, and absence of sto- 

 mata. Draw. 



Make a longitudinal section through the growing tip in 

 the plane of the branch, and note 



6. The sheath composed of one or more sets of thickened 

 and partly coalesced bracts. These bracts may be 

 detected in various stages of growth, all originating 

 behind 



7. The growing point. 



8. The growing tips of rudimentary roots and branches. Note 

 the exogenous development of a branch, all the tissues 

 of the stem entering into it, and the endogenous devel- 

 opment of a root, distinct from the tissues of the stem 

 and pushing its way through them. 



C. THE BRANCH (Aerial Stem). In a transverse section, 

 with a low power, notice 



1. The single row of epidermal cells. 



2. The loose, round-celled fundamental parenchyma, with 

 large intercellular spaces. 



3. The fibro-vascular bundles, consisting of 



a. The light colored portion, phloem. 



b. The shaded portion, xylem. 

 Under high power notice 



4. The epidermis and hypoderma. Note 



